Introduction
In IT project management, this age-old question frequently pops up in discussions: “Agile vs Waterfall – which methodology is better?” Often, responses will be strongly skewed to one side or the other; classic project managers would claim that Agile is loose, ungoverned, and informal due to its adaptive nature, with some even going as far as saying “Agile is Fragile”. Meanwhile, on the other side of the fence, Agile proponents would claim that Waterfall is rigid, constraining, and unprogressive – claiming it to be old fashioned and outdated.
For those unfamiliar with these two methodologies, the natural question arises: “Is one approach truly better than the other?” Having delivered countless projects and worked in organisations that embrace either of these methodologies, I have seen the good and bad of both. The real question that we should ask is: “Which methodology fits our specific circumstances best?”
In this article, we will explore both methodologies’ strengths and weaknesses to help you decide which is right for your projects and organisation.
Waterfall
Waterfall is the traditional, linear project management methodology often associated with large-scale construction or engineering projects. It follows a sequential process, with each phase – requirements gathering, design, development, testing, and deployment – clearly defined and dependent on the completion of the previous one. The method is often visualised as a cascading waterfall, where progress flows downward through distinct phases.
In a typical Waterfall project, the team starts by gathering requirements, which are finalised before moving into design. Once the design is signed off, the development begins. After development, the product is tested and then delivered to the customer. This approach provides clear milestones, making tracking progress straightforward. Waterfall is well-suited for projects with fixed scope, timeline, and budget – for example, large-scale infrastructure projects or system migrations with hard deadlines.
However, this tightly coupled process has drawbacks. Delays in one phase often create cascading delays in others, making it hard to recover without extending the timeline or compromising quality. Additionally, since each phase relies on the previous one, teams are engaged at different times, leading to potential inefficiencies and bottlenecks.
Agile
Agile, in contrast, takes a cyclic, iterative approach. Originating in the 1950s as a method for software development, Agile emphasises flexibility and continuous improvement through short, manageable work packages called iterations or sprints. Each iteration goes through its own mini cycle of planning, design, development, testing, and release. This allows teams to refine the product and adapt quickly to feedback.
Agile keeps the entire team engaged throughout the project, promotes early and continuous customer feedback, and reduces dependencies between tasks, enabling multiple teams to work in parallel. This is especially beneficial in software development, where requirements and priorities may shift over time. However, Agile’s flexibility can also introduce challenges – especially when it comes to defining clear milestones and managing shifting scopes.
Side-by-side comparison
To provide further clarity between the 2 methodologies, we can list out the common strengths and weaknesses of both in a side-by-side comparison, as follows:
|
|
Waterfall |
Agile |
|
Flexibility |
· Fixed scope, timeline, and budget · Addresses change via change requests |
· Adaptable and flexible as work is based off a broad backlog · Backlog items are prioritised throughout the project instead of being locked at the start |
|
Timeline |
· Linear timeline with a clear path of progress |
· Short, iterative cycles · Harder to establish milestones for long term deliverables |
|
Planning |
· Front-loaded planning activities at the start of the project · Adjustments throughout the project to cater to changes |
· Ongoing planning throughout the project (e.g. sprint planning) |
|
Cost |
· Fixed cost based on agreed scope and deliverables |
· Variable cost – usually managed as time & materials |
|
Deliverables |
· Final product delivered at the end of the project |
· Incremental delivery of working products · Regular showcases to demo the product in progress |
|
Team structure |
· Clearly defined roles and responsibilities |
· Self-organising, cross functional teams · May require coaching for less experienced teams |
|
Customer feedback |
· Limited feedback at the end of the project |
· Continuous feedback and customer engagement throughout the project |
Which approach is right for me?
Waterfall works better for projects with clearly defined scope, strict deadlines, and a fixed budget. Examples include on-premise to cloud migration with specific data center exit dates, or large-scale system upgrades like moving an organisation from Windows 10 to Windows 11.
Agile is better suited to projects with a broad, evolving scope and flexible timelines, like app development, where high-quality output is prioritised over a fixed release date. It’s particularly favoured in tech companies or DevOps teams that continually improve cloud infrastructure and processes.
Hybrid methodologies: Can they co-exist?
With both methodologies offering distinct benefits, many of our customers are adopting hybrid approaches, combining the strengths of both to suit their needs. This could mean using Waterfall’s front-loaded planning and discovery phases, followed by Agile’s iterative build, test, and release cycles. Alternatively, teams may implement Agile’s ongoing iteration while employing Waterfall’s “big bang” release approach for large migrations.
At an organisational level, Agile and Waterfall often co-exist across different departments. IT and development teams might work in Agile while finance or PMO teams stick to Waterfall for managing fixed deadlines and budgets. Ultimately, the goal is to customise the approach to fit the project and business objectives.
Summary
In the end, the question isn’t whether Agile or Waterfall is better – it’s about choosing the right tool for the job. Each methodology has its strengths and weaknesses, and the key to success is understanding the needs of your organisation and project. The methodology you choose is simply a vehicle to deliver value and achieve your business outcomes.
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